What are the signal lights on top of the air intake in Formula 1 cars for?

What are the lights just behind and on top of the driver's head for?

They signal if the battery unit and ERS-unit are in a safe state. If there are green lights on them, then the car can be touched as it is considered to be safe. If it is red, then there is a risk of an electric shock. These signal lights are in place for the stewards and mechanics working on the car.